Ive thought about the following for now.
1. taking a pic
2. switching on gps to track
3. sending a text back ( with IMSI/location/etc)
4. callback with screen off and mic enabled
5. remote wipe
6. lock phone and never be able to unlock ( manually , but a secret text msg can unlock it of course when you get it back :-) )

trying to keep it minimalistic to start off with

however , these are just ideas that I have, and faint knowledge on how to go about it,
will start some serious work once ive sorted out some time for myself from the daily bread earning boring stuff that I do 9am-5pm !